I am no expert. The pic of her at 2.5 months looks like a hemangioma to me.
As I am finding with going through all of this (dealing with a hemangioma and now another vascular issue with my daughter) is that nothing is textbook. I had a friend whose daughter had a segmental hemangioma on her face and she DID have a faint mark at birth. It just took a few weeks to progress into something more.